Driverless vehicle conveyor systems of the general type involved herein are known. For example, see U.S. Pat. No. 3,858,262 which discloses a closed loop system wherein two straight sections of track have their ends interconnected by turn tables. After analyzing known systems, it has been concluded that they lack versatility.
There is a need for such a conveyor system which is adaptable for use as a small system (such as 12 feet wide and 30 feet long) and as a large system (such as more than 30 feet wide and more than 100 feet long). There is a need for such a system which is versatile in that it should not be limited to rounded ends but rather can have a closed loop which is rectangular, in a form of a pentagon wherein two straight sections have an included angle which is other than 90.degree., etc. There is also a need for a system of this general type which is less expensive, lighter in weight, and less complicated than prior art systems.
It has been concluded that in order to design a system having the attributes described above, such a system should not include a turntable. A turntable takes up too much space in a small system and is impractical in a large system. Turntables are further objectionable insofar as they require the use of reversible electric motors, special gears and bearings, which are expensive to purchase, use and maintain. At the same time, the system should be continuous and completely automatic while providing for accumulation of vehicles at predetermined locations as well as accumulation when one vehicle contacts another.